Stabilizing means for plastic reinforced paperboard lug box

ABSTRACT

A plastic and paperboard lug box type produce container, comprised of a rectangular paperboard container having sides and ends, a bottom, and lids hinged to the upper edges of the sides, and rectangular, plastic end frames forming caps to receive limited portions of opposite ends of the container, the end walls of the container being stiffened against warpage out of their normal planes by bending a narrow flap therefrom on a horizontal hinge line, and there being lugs formed on the end frame to penetrate apertures in the end walls of the container, with hook ends thereon to engage over edges of these apertures and hold the end walls snugly against the end frames. The end frame has flanges which engage and overlap end portions of the container side walls, and rivets or staples secure these overlapped parts to secure the end frames and boxes in proper assembly notwithstanding repeated stresses in shipment over long hauls.

United States Patent 51 Oct. 28, 1975 Crane Primary ExaminerDavis T. Moorhead l l STABILIZING MEANS FOR PLASTIC Arrorney, Agent, or FirmForrest J. Lilly REINFORCED PAPERBOARD LUG BOX [75] inventor: Walton B. Crane, Sherman Oaks.

Calif.

{57] ABSTRACT A plastic and paperboard lug b tainer, comprised of a rectang ox type produce con [73] Assignee: A & E Plastik Pak Co., Inc., City of ular paperboard con m m4 7 9 l "1 5 d M n" l k H 2 2 l to the upper edges of the sides, and r UNITED STATES PATENTS flanges which engage and overlap end portions of the container side walls, and rivets or stap overlapped pans to secure the '53 mm ho t m t mm s ca 8 m S emP l fir g d n.m ed

in proper assembly notwithstan in shipment over long hauls.

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Crane.,,.....i.i.,...u Belchermuumm 0 p a R 4880 6666 9999 i111 23 2 11 523 42039 .9 395- 6700000 5. 33333 US. Patent Oct. 28, 1975 STABILIZING MEANS FOR PLASTIC REINFORCED PAPERBOARD LUG BOX BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to containers of the lug box type, and particularly to those made of paper board or any other suitable semi-flexible container board, reinforced by plastic or sheet metal end frames which fit onto the container board forms like rectangular end caps.

2. Description of the Prior Art A lug box container representative of the prior art is disclosed in my copending application Ser. No.

307,962, filed Nov. 20, 1972, now US. Pat. No. 3,878,980. It is comprised of a rectangular container board box or container, made preferably from a single blank, and comprising a bottom, side walls turned up from the longitudinal edges of the bottom, lids hinged to the upper edges of the side walls, and end walls turned up from the end edges of the bottom wall. The vertical edges of the end walls have hinged thereto side flaps which overlap and are glued face-to-face to the side walls for connection and reinforcement.

The material of the container board may be, preferably, well known semi-rigid corrugated paperboard, or any suitable equivalent stock which may be bent along scored bend or hinge lines.

Applied over the ends of the container are stiff or rigid reinforcing frames of open rectangular configuration which are preferably unitary molded plastic shapes, or can be fabricated from sheet metal. These frames have coplanar flanges which seat against the outer surfaces of the end walls, and flanges perpendicular to the coplanar flanges which fit snugly, like caps, over narrow end portions of the container. The hinged lids remain outside these caps. The upper and lower perpendicular frame flanges provide, or have thereon means providing, interengageable substantially horizontal stacking surfaces such that a number of the containers may be stacked, frame against frame, in vertical columns. The flanged construction of the plastic end frames provides the latter with sufficient strength and rigidity in their vertical edgewise directions to withstand, without buckling or collapsing, the maximum stacking loads normally encountered when the containers are stacked in their filled condition.

The upper and lower perpendicular frame flanges are relatively thin, and have, respectively, substantially horizontal upwardly and downwardly facing exterior side surfaces thereon. Extending vertically outward from the exterior side of one of these upper and lower perpendicular flanges, preferably the upper flange, is a spacer means, which has thereon one of said substantially horizontal stacking surfaces, (which may be in one or more coplanar sections) which is thus spaced outwardly from the correspondingly facing exterior side surface of the flange. The oppositely facing stacking surface is then the aforementioned substantially horizontal exterior surface on the other of these upper and lower perpendicular flanges.

SUMMARY OF THE PRESENT INVENTION The present invention provides improvements in the prior paperboard lug box described in the preceding paragraphs in strength, stiffness, and security, and especially in the support of the paperboard box ends in fixed vertical planes, without warpage to which the boxes of the prior art we re sometimes subject. To maintain the box ends in a good coplanar condition, I provide a fold or score line horizontally thereacross, near one of its horizontal edges. and then support the long narrow flap so provided at an obtuse angle to the plane of the end wall, so that any bending stress thereacross is resisted or prevented. I then lock the end walls of the paperboard box flush and flat against the upper and lower coplanar flanges of the end frames by locking elements projecting from said flanges through locking notches in the end walls. Finally, I secure the extremities ofthe side walls of the container to the overlapping vertical perpendicular flanges of the end frames, preferably by metal rivets or staples, giving the box maximum security in this region.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a complete lug box in accordance with the invention;

FIG. 2 is an exploded view thereof showing the components of the box prior to assembly;

FIG. 3 is a vertical section taken on the broken line 33 of FIG. 1;

FIG. 4 is a vertical detail section taken on line 4-4 of FIG. 1;

FIG. 5 is a fragmentary side elevational view, enlarged, looking in the direction indicated by the arrow 5 in FIG. 3;

FIG. 6 is an enlarged perspective view of a detail seen in FIG. 1;

FIG. 7 is a detail section taken on line 7-7 of FIG. 1; and

FIG. 8 is a detail section taken on line 8--8 of FIG. 5.

DESCRIPTION OF AN ILLUSTRATIVE EMBODIMENT The reinforced paperboard container 10 has a body 12, and rigid reinforcing end frames 14 made of a molded thermoplastics material. Body 12 can be of any suitable container board. Without limitation thereto, the invention will be described where the container is constructed from a blank 16 of corrugated paperboard or other suitable paperboard material. The blank 16 is folded in the manner illustrated in FIG. 2 to its final shape of FIG. 1. Plastic end frames 14 are then applied over and secured to the ends of the body, but with the presently mentioned hinged lids of the container outside the end frame.

Referring to FIG. 2, the container blank 16 has a rectangular bottom wall 18 with end and side edges. Joined to these edges of the bottom wall along scored or creased fold lines 20 are end walls 22 and side walls 24. Joined to the ends of the end walls 22 along fold lines 26 are flaps 28. A pair of slots 21 intersect each fold line 20. Lids 30 are hinged to the upper edges of the side walls 24 along hinge lines 32. The end edges 33 of these lids are offset from the vertical end edges of the side walls 24 by a distance which is substantially equal to or slightly greater than the widths of the end frames I4. Thus there are shoulders at 331', which are substantially extensions of hinge line 32, though preferably with a slight downward slope, along which the lids 30 are unconnected with the side walls 24. At the swinging corners of the hinged lids are locking tabs 33a which may project substantially to the plane of the end walls of the container, forming locking shoulders 33b.

The container blank I6 is erected by folding the end walls 22 upwardly and folding the end wall flaps 28 inwardly normal to the end walls. The side walls 24 are then folded upwardly against and adhesively bonded to the inwardly folded flaps 28. The lids 30 are foldable on their hinge lines 32 to closed positions over the open top of the container body.

Each end frame 14 comprises a rectangular integral structure embodying four coplanar flanges, an upper flange 34, a lower flange 35, and side flanges 36, which overlie marginal portions of the end walls of the container, and engage flat thereagainst. In addition, the frames 14 include four flanges 38, 39 and 40 extending perpendicularly from the outer edges of the flanges 34, 35, and 36, the flange 38 being an upper flange, flanges 39 being side flanges, and flange 40 being a lower flange. These snugly fit on over limited end portions of the bottom and side walls of the container, and go on over the end walls 22, forming end caps. The lids 30 remain outside. Means in accordance with the present invention for securing the end frames on the container, and for supporting the end walls in good planar positions, will be described hereinafter.

Centrally located on and extending vertically upward from a substantially horizontal upwardly facing exterior surface on the upper side of the upper perpendicular flange 38 of each end frame 14 is a spacer means 46 whose top forms a substantially horizontal, elevated stacking surface, and which is cored out to form a horizontally disposed recess 44. The recess opens outwardly and serves as a handle, giving proper room for the fingers. The spacer structure 46 is of the same width as the upper frame flange 38. Its top surface constitutes a support for the bottom perpendicular flange 40 of the end frame 14 of the container just above in a vertical stack of such containers.

The aforementioned spacer 46 occupies a central position on top of the flange 38, extending for a distance as shown along the flange 38. Occupying opposite end portions of the flange 38, and spaced from opposite ends of the spacer 46, are elevated spacers 50, with flat horizontal tops forming substantially horizontal stacking surfaces coplanar with that at the top of spacer 46, and cored out, as seen in FIG. 2.

Thus, a given container, when stacked on a container below, will have the substantially horizontal lower exterior surface on the lower side of its lower flange 40 in engagement with and resting upon the three spacers 46 and 50. It thus comprises the lower stacking surface of the end frame.

The weight of a stack of containers is thus transferred through the plastic end frames of the containers rather than through any paperboard portions of the latter.

The ends of the spacers 50 confronting the handle 44 have hook-forming projections 60, forming therebelow tapered throats 6], which are adapted to engage over and receive the opposed shoulders 33h formed on look ing tabs 33a, projecting laterally from the end edges 33 of cover panels 30. The end edges 33 extend alongside the spacers 50 to meet shoulders 331 which are approximately aligned with hinge line 32 and are formed along the top edge of each side wall 24 outwardly of the lids 30.

Now, when the lids or top panels are to be folded in and over a filled carton, the tab 33a of a corner portion 70 of the lid engages the tapered tip of the projection 60, and by pressing downwardly on the corner portion of the lid just outwardly thereof, the tab slides down the incline and into the throat 61.

On each end frame, running entirely around the end flanges 34, 35 and 36, excepting at the location of the handle, is a rounded bead 86, which serves as a buffer against containers of an adjacent stack. The underside of the bead on the lowermost flange leads to a bevelled surface 87, which facilitates penetration by the blades of a conventional clamp truck by which a carton can be conveniently lifted from the floor, or from a conventional pallet as shown in FIG. 1.

Projecting upwardly from each of the spacers 50 is a tapering positioning prong 88, adapted for reception, with small clearance, in an aperture 89 formed in the lower flange 40 of an end frame immediately above. The paperboard box structure is apertured at 21 suitably to permit entrance of these prong structures.

In the particular design of the end frame here shown for illustrative purposes, the inner edge of each vertical coplanar flange 36 merges with or is completed by an integral vertical column portion 90, displaced outwardly from the flange 36, and also outwardly beyond the aforementioned bead 86. This column portion 90 preferably has a transverse indentation 91, to the depth of a plane tangent to the bead 86, for a purpose to be mentioned hereinafter.

Returning now to consideration of the end walls 22 of the container, it has been found in practice that when these are constructed of conventional paperboard or the equivalent, such as conventional corrugated board, there is a tendency for undue warpage under certain conditions. and for the fastenings to the end frames to pull loose. The present invention affords means acting to hold the end walls in improved planar condition, in secure connection to the end frames, as will now be described.

First, to hold the end walls 22 in a planar condition, I form them, in parallelism with, and spaced a short distance from one horizontal edge (preferably the top edge) with a horizontal score line 92. In the embodiment here shown, this score line is a short distance down from the upper edge, and the score line is on the inner face of the wall, so that the horizontal edge flange or flap 93 so formed tends to hinge or bend inward, as seen best in FIG. 3, to a substantial angle relative to the vertical plane occupied by the rest of the end wall. Held in this position, the end wall is stabilized by the hinge line against any harmful warpage.

It will of course have been noted that the main vertical panel of the end wall 22 abuts the inside surfaces of the coplanar flanges 34, 35 and 36 of the end frames. Just below the central spacer and handle structure 46, the end frame member is formed with an angular wall 96, longitudinally coextensive with the structure 46, and longitudinally apertured as at 97. This wall 96 is formed with a depending lip 98 serving as an abutment or catch for the upper edge of the end wall flap 93, holding it in the angular position of FIGS. 1 and 3. The upper edge engages snugly under the lip 98, the flap 93 bridging across the aperture 97, when the end wall 22 has been seated against the upper and lower coplanar flanges 34 and 35 and over the perpendicular flange 40. as seen in FIGS. 1, 3 and 4. The flap 93 also engages angular webs 108 which also deflect them angularly on the hinge line 92.

Each upper end frame coplanar flange 34 is formed adjacent its lower edge with a pair of horizontally spaced, short, perpendicularly projecting locking elements or flanges 98a, recessed and shouldered on their undersides to form down ardly facing hooks 99a, and the lower end frame coplanar flanacs 35 are formed adjacent their upper edges with a similar pair of recessed and shouldered flanges 98h formed to provide similar but upwardly projecting hooks 99/2.

The end walls 22 of the container are severed, and scored on their inside surfaces, to provide inwardly folding flaps 100a and 1001) opposite the hooks 99a and 99/2. The three-edged apertures lOl resulting from the making of these flaps nicely receive said hooks, and

permit them to engage over the horizontal aperture edges [02. As will appear, the hooks 99a and 99b face downwardly and upwardly, respectively, and the flaps 100a and 10011 are hinged at their upper and lower edges, respectively, in the illustrative embodiment. Preferably, the hinge line of the upper flaps coincides with the score line 92.

In the assembly of the container, the upper flap 93 is engaged upwardly against the frame lip 98, and the end wall 22 pressed into the frame, the upper edge flange or flap 93 of the end wall bending on the hinge line 92 by reason of engagement of the flap 93 against angular wall 96 and webs 108. The locking elements 98a and 98b simultaneously force the flaps [00a and 1001) back, until their hook ends engage over the end wall edges 102 afforded by the cutting of said flaps. Thus, mar ginal portions of the end walls 22 overlap, engage and are locked to marginal portions of the frame flanges 34 and 35.

The aforementioned slots 21 along the container end score line are centered with the columns 90, and aligned therewith are vertical apertures 89 in the bottoms of the end frames, positioned to receive and laterally locate projections 88 on the end frame of a container immediately below. These apertures are between bracing webs 104.

The overlapping side perpendicular flanges 39 of the end frames are then riveted to the underlying end edge portions of the side walls 24 by suitable heavy rivets 110, as shown particularly in FIGS. 1 and 7. The rivets can be either plastic or metal, but metal is preferred; and heavy staples can also be used.

The combined achievement is stability and bracing against warpage of the end walls, and added overall strength to the container. The hinge line and flap keep the end walls of the paperboard container against undue warpage, since the end wall cannot bend materially transverely of the hinge. At the same time, the end walls below the hinge line are secured flush against the horizontal, upper and lower coplanar flanges of the plastic end frame, while the riveting or stapling of the side or end perpendicular flanges of the end frames to the underlying end portions of the side walls of the container place the rivets or staples in shear, and thus maximize the strength of the fastening.

\'arious changes within the scope of the invention may of course be made without departing from the scope of the appended claims.

What is claimed is:

l. in a generally rectangular container with rigid rectangular, reinforcing end frames at opposite ends thereof, the container having rectangular bottom, side and end walls, and lids which are hinged to the upper edges of said side walls, said rectangular end frames comprising integral, coplanar, upper, lower and side flanges parallel with the end walls ofthe container and lying thereadjacent, and rectangular integral upper, lower and side flanges, integral with and projecting perpendicularly from said coplanar flanges from the outer margins thereof, whereby to provide reinforcing caps receiving therein the corresponding end walls of the container and end portions of said bottom walls, with the perpendicular side flanges thereof lying closely adjacent said side walls of said container;

each of said end walls having a horizontal score line near one horizontal edge thereof and the flap so formed being bent through an acute angle on said score line, whereby to resist warpage of said end wall transversely of said score line.

2. The subject matter of claim 1, wherein said score line is near the upper edge of each end wall, and the flap formed thereby is bent inwardly relative to the container through an acute angle relative to the plane of the end wall.

3. The container of claim 1, including means on the end frames engaging said flaps to force them into and to hold them in said bent positions.

4. The container of claim 2, including means on the end frames engaging said flaps to force them into and to hold them in said bent positions.

5. The container of claim 1, wherein:

portions of the perpendicular side flanges of the end frames overlap adjacent portions of the side walls of the container; and including fastener elements penetrating said overlapping portions of said side flanges of said end frames and side walls of said container.

6. The subject matter of claim 3, including also:

headed prongs on and projecting from said upper and lower coplanar frame flanges and cooperating apertures in said end walls of said container which receive and engage behind the heads of said prongs to releasably hold said end walls snugly against said frame flanges.

7. The subject matter of claim 3, in which said flap engaging means comprise walls of angular profile on said end frames engaging the upper edges of said flaps to support them in said bent positions. 

1. In a generally rectangular container with rigid rectangular, reinforcing end frames at opposite ends thereof, the container having rectangular bottom, side and end walls, and lids which are hinged to the upper edges of said side walls, said rectangular end frames comprising integral, coplanar, upper, lower and side flanges parallel with the end walls of the container and lying thereadjacent, and rectangular integral upper, lower and side flanges, integral with and projecting perpendicularly from said coplanar flanges from the outer margins thereof, whereby to provide reinforcing caps receiving therein the corresponding end walls of the container and end portions of said bottom walls, with the perpendicular side flanges thereof lying closely adjacent said side walls of said container; each of said end walls having a horizontal score line near one horizontal edge thereof and the flap so formed being bent through an acute angle on said score line, whereby to resist warpage of said end wall transversely of said score line.
 2. The subject matter of claim 1, wherein said score line is near the upper edge of each end wall, and the flap formed thereby is bent inwardly relative to the container through an acute angle relative to the plane of the end wall.
 3. The container of claim 1, including means on the end frames engaging said flaps to force them into and to hold them in said bent positions.
 4. The container of claim 2, including means on the end frames engaging said flaps to force them into and to hold them in said bent positions.
 5. The container of claim 1, wherein: portions of the perpendicular side flanges of the end frames overlap adjacent portions of the side walls of the container; and including fastener elements penetrating said overlapping portions of said side flanges of said end frames and side walls of said container.
 6. The subject matter of claim 3, including also: headed prongs on and projecting from said upper and lower coplanar frame flanges and cooperating apertures in said end walls of said container which receive and engage behind the heads of said prongs to releasably hold said end walls snugly against said frame flanges.
 7. The subject matter of claim 3, in which said flap engaging means comprise walls of angular profile on said end frames engaging the upper edges of said flaps to support them in said bent positions. 